Center finder for drill bits and the like



i3; [.ICWINKO 2,427,290 CENTER FINDER FOR DRILL BITS AND THELIKE .sgpt. 9,1941

. j med Nov. 27. 1944 Boles/01d Zzcakmza.

Patented Sept. 9, 1947 CENTER FINDER FOR DRILL BITS AND THE LIKE Boleslaw Licwinko, Conshohocken, Pa.

Application November 27, 1944, Serial No. 565,355

1 Claim. 1

My invention relates to improvements in center finders for the drill bits of drill presses, and the like, the primary object in View being to provide a simple form of device adapted to be applied directly to such bits for use in quickly and accurately centering the bits relative to the axes of holes, bores, and the like, to be drilled into Work, and which functions to guard and protect the bits during center finding operations.

To the accomplishment of the above, and subordinate objects presently appearing, a preferred embodiment of my invention has been illustrated in the accompanying drawing, set forth in detail in the succeeding description, and defined in the claim appended hereto.

In said drawing:

Figure 1 is a view in side elevation of my improved center finder applied to a drill bit,

Figure 2 is a similar view showing the center finder in longitudinal section, and

Figure 3 is a view in longitudinal section of the center finder, detached, and drawn to an enlarged scale.

Reference being had to the drawing by numerals, my improved center finder, as shown, comprises a sleeve-like body I, preferably cylindrical, and of any suitable length, provided with a cylindrical bore 2 of substantially the same diameter as that of a drill bit 3 to which the center finder is to be applied, and a solid conical leading end portion 4 tapering to a point 5 in the axis of said bore 2. At the bottom of the bore 2, a, conical recess 6 is provided in the inner face of the leading end portion 4 surrounded by a fiat annular shoulder l. The trailing end of the body I is rounded off, as at 8, to obviate sharp edges. The described device may be formed of any suitable metal.

In using the described center finder, the same is slipped over the leading end of the drill bit 3 while the latter is backed, oil. of the Work sufficiently for that purpose. When completely applied, the shoulder 1 engages the front end cutting edges 9 of said bit and thus establishes the completely applied position of the center finder. As will be noted, particularly in Figure 2, the shoulder 1 is of right angled form in cross section and thereby presents a corner against said edges 9 providing for minimum surface engagement between said shoulder and edges obviating injury to the edges in the application and use of the center finder. As will also be noted, in the completely applied position of the center finder, the point portion of the drill bit 3 is accommodated in the recess '6 clear of the same, thereby obviating injury to the pointed portion of said bit. With the center finder applied, as described, the work, not shown, and the bit are relatively adjusted, in the usual manner, to locate the point 5 of the center finder on aselected one of the usual spotting centers, not shown, on the work, thus centering the bit 3. The bit 3 is then backed off from the work sufficiently to permit the centering device to be removed.

The foregoing will, it is believed, su-fiice to impart a clear understanding of my invention without further explanation.

Manifestly, the invention, as described, is susceptible of modification without departing from the inventive concept, and right is herein reserved to such modifications as fall within the scope of the appended claim.

What I claim is:

A center finder for use on a drill bit compris ing a sleeve-like body having a cylindrical bore of substantially the same diameter as that of said bit, and a conical solid leading end portion tapering to a point in the axis of said bore, said portion being provided at the bottom of said bore with a countersunk recess adapted to accommodate the point of said bit and an annular shoulder around said recess adapted to engage the front cutting edges of said bit and spacing the point of the bit from said bottom to prevent injury to said point.

BOLESLAW LICWINKO.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,296,087 Burns Sept. 15, 1942 1,185,570 Zinn May 30, 1916 1,220,792 Smith Mar. 27, 1917 -2,306,762 Stanfield Dec. 29, 1942 

